1. Field of the Invention
This invention relates to a method for producing food, more particularly, to a novel method for processing Alaska pollack roe in the production of fish roe products, in particular, salted Alaska pollack roe and karashi-mentaiko (Alaska pollack roe pickled in red pepper sauce).
2. Description of the Prior Art
In general, the qualities of Alaska-pollack roe (roe qualities) widely vary depending on, for example, the season, area and method of fishing, the post-fishing storage conditions and the method for roe collection. For example, the roe of Alaska pollack fish caught in the spawning season near the spawning ground attains a high maturity and has a large ovary. In contrast, the roe not yet reaching the spawning season has a small ovary and shows immature development. Further, the roe qualities vary depending on the post-fishing storage conditions. When pressure or impact is applied to a fish body, for example, the adhesion of bile pigments to the ovary and the infiltration of hemachromes from the intestinal tracts are liable to occur. When a fish body is overcooled, it is sometimes observed that some part or the whole of the ovary is frozen.
Furthermore, it is sometimes observed that an inappropriate roe collection method or an unsuitable treatment of roe after collection would cause cutting in the ovary, breakage of the ovarian membrane or roe granules or contamination of roe with the internals other than the ovary. In addition, a wide variety of materials, which are liable to undergo changes, are employed, since the size of the ovary varies depending on the age and body size of fish. In other words, the feedstock materials vary widely.
Accordingly, there is a difficulty that feedstock materials should be severely selected and, at the same time, a method for processing the material should be modified depending on the qualities of the roe thus selected. It is highly difficult to establish definite standard conditions for a method for producing an Alaska pollack roe product. Under the existing circumstances, therefore, Alaska pollack roe products are produced in accordance with the conditions of feedstock materials depending on the perception and experiences of the persons in charge.
Salting is the most important step in the production of an Alaska pollack roe product. In the step of salting, water is added to roe together with, for example, salt (sodium chloride), seasonings and colorants and mixed. In this step, there has been used a rotary cask whereby the roe and additives contained therein are well mixed by rotating, thus promoting the migration (penetration) of the salt, seasonings and colorants into the roe. However, the rate of migration of substances into the roe varies depending on the type and concentration of the substances. Thus, uniform migration into the center of the roe cannot be sufficiently achieved. In addition, as discussed above, the qualities of the product widely vary depending on the conditions of the roe employed as the feedstock material, which brings about a serious problem in the production of Alaska pollack roe products.